1. Field of the Invention
The present invention relates to a passenger protection system such as an air bag system in automotive vehicles, and more particularly to an electric control circuit for the passenger protection system.
2. Description of the Prior Art
In U.S. Pat. No. 4,222,030 to Yasui et al. issued on Sep. 9, 1980, there is disclosed a passenger protection system having an electrically operated actuator for a gas generator. The passenger protection system includes a primer connected to collision sensors, each sensor is in the form of an acceleration sensor mounted on the front portion of the vehicle. The primer is electrically fired upon acceleration of the vehicle in excess of a predetermined magnitude thereby allowing the gas generator to supply gaseous fluid, under pressure, from the gas generator into an inflatable air bag. In addition to a primary electric power source in the form of the vehicle battery a back-up condenser is provided as a secondary electric power source to ensure a supply of electric energy to the primer. The conductors leading from the collision sensors to the primer, however, are momentarily delayed due to a distance between the collision sensors and the actuator. The practical embodiment further includes a electric energy to the primer, the conductors and collision sensors. This results in a shortage of electric energy for the primer due to a voltage drop caused by internal resistances of the conductors and collision sensors. Such a shortage of electric energy is increased when there is a plurality of primers adapted to the actuator.